YLEM Journal volume 27 issue 6

YLEM

JOURNAL

Artists Using Science and Technology
Volume 27 No. 6 May/June 2007

Autonomous Robots That Paint

Max Chandler's Gimpy 2, and Leonel Moura s robotic action painter

AUTONOMOUS ROBOTS THAT PAINT

Loren Means

I think of robots as works of art, and roboticists as artists,
as well as philosophers. So I’m doubly delighted when I run
across roboticists who create robots that themselves create art.

The history of robotics has two phases: first, the top-down
approach, and second, the bottom-up approach. The top-down
approach posited a robot that was intelligent enough to under-
stand most aspects of its environment before venturing into it.
The problem was, these robots were never intelligent enough,
and so took an inordinate time to plot each motion in the world.
The bottom-up approach, pioneered by Rodney Brooks, put
many robots with low intelligence into the world with little
knowledge of their environment, and allowed them to learn
how to function on their own. In the process, two concepts
helped the robots manifest themselves. One such concept was
swarm intelligence, the mimicking of natural entities such as
birds, bees, and flies in the way they cooperate to achieve goals,
and stigmergy, the ability of these entities, such as ants, to
communicate with each other without encountering each other
directly, for instance by the planting of pheromones by one ant
to suggest corresponding behavior in other ants.

Science fiction writers such as Olaf Stapeldon, Isaac Asimov,
and Vernor Vinge have postulated group minds that, in coop-
erating with each other in adequate numbers, are able to create
an intelligence that rivals that of an individual human. Swarm
intelligence, on the other hand, creates an intelligence that
mimics non-human intelligence, and the art created by these
swarm intelligences is itself a manifestation of forms that are
like those found in nature, rather than the kinds of mimetic art
that human artists are taught to execute. In other words, the art
is non-objective, or “abstract,” and often of a very high order.
This intelligence is closer to “machine intelligence” than human
intelligence.

Although the creation of art by computers, using generative
techniques, has produced a formidable body of work, the
creation of art by autonomous robots is relatively new, prob-
ably because the bottom-up approach deprives robots of the
processing power that today’s computers make available for
artistic creation. Computer-art algorithms usually consist of
two essential elements: a generative element that allows the
computer to create, and an aesthetic neural network that evalu-
ates the quality of the work created and tells the computer what
to discard, and when a work of art is finished.

Leonel Moura’s swarm robots don’t have the individual pro-
cessing power to manifest neural networks, and so he found

it necessary to intervene and stop the swarm process when he
felt the work was completed. His new RAP robot, on the other
hand, has more aesthetic ability, and can finish and even sign
its own works. Max Chandler’s robots are closer to the RAP

model, but Chandler is intimately involved in the painting pro-

2 YLEM JOURNAL: Vol. 27, No. 6

EDITORIAL

cess with his robots, loading their paint containers and stopping
the painting process to wait for paint to dry.

Since I do generative art in both the visual and the sound me-
dia, and try to get similar results in both, I’ve been pondering
the differences between the two. I think the fundamental differ-
ence is that music is a strictly temporal art, like dance and the-
ater, in that no object is created. Visual art, on the other hand,
produces an object, and that object constancy is what makes it
easier to generate complex forms. When you make music, you
have to keep remaking it from second to second, as it evapo-
rates, as Eric Dolphy put it, “into the air.” Whereas when you
make a mark on a surface, the mark remains, and accumulates
as more marks are added, until complexity is achieved. These
marks that remain can serve as the equivalent of pheromones,
which would suggest why robots paint, but, as far as I know,
don’t as yet make music. (Although Tim Blackwell has used
swarm intelligence with improvising jazz musicians for several
years, creating computer graphic displays that the musicians
react to: http://www.timblackwell.com.)

Max Chandler is a long-time YLEM supporter who splits his
time between San Francisco and Scottsdale, Arizona. He has
been interviewed in NewScientist, and has shown his robots at
Siggraph and RoboNexus. Chandler studied math at MIT, Chi-
nese at the Defense Language Institute, and did graduate study
work with the Taiwanese painter Chen Ting-shih. Chandler
has worked in both hardware and software with ten patents in
milk cartons, gymnastic equipment, scanners, film recorders,
compiler techniques, CAD, and UI. He also programmed such
products as Laplink, SimCity 3000, and The Sims. As he put it
in a recent interview: “I think reality has three components: the
material world, the natural laws that describe how that world
behaves, and the mathematics at the foundation of those laws.
To me, art that considers each of these components is much
more realistic than paintings that look like photos.”

I found Leonel Moura on the Web at www.lxxl.pt while doing
research on swarm robotics. Moura is a Portugese conceptual
artist who has worked with AI and robotics since 2001. In
2003, he created his first swarm of ‘Painting Robots’ able to
produce original artworks based on emergent behavior. Since
then he has produced several Artbots, each time more autono-
mous and sophisticated. RAP (Robotic Action Painter), 2006,
created for a permanent exhibition at the American Museum

of Natural History in New York, is able to generate highly cre-
ative and original art works, to decide when the work is ready
and to sign it, which it does with a distinctive signature. In 2007
he opened the Robotarium, the first zoo dedicated to robots and
artificial life, in Portugal. Moura has written several books on
the subject, among which are Architopia, 2001, Man and Robots,
2004, and Robotarium, 2007.

YLEM FORUM

YLEM Forum: Accessing Biology Through Art
Thurs., November 8th at 8 pm

Canessa Gallery

708 Montgomery (upstairs)

San Francisco, CA

As this program shows, biology in so many ways is a very
visual subject. At the molecular level, this is more of a problem,
but one of the speakers, a graduate in microbiology, manages
to convey its ideas using vivid paintings that use, on occasion,
metaphors from mythology. Learn more about biology in an
enjoyable way!

PROGRAM

Donna Billick: Paintng murals with science students
“Neither science nor the arts can be complete without combining thetr
separate strengths”

-E. O. Wilson.

Our Art/Science Fusion program is a new paradigm for teach-
ing and learning at the University of California Davis Campus.
Through interactive, experiential-based lectures and studio
time, students learn scientific concepts and turn them into
works of art. The unity of knowledge is introduced, a sharing
across borders and disciplines, where students see and feel art
and science in the context of creating art, using the mediums of
ceramic, paint and textiles. With this experience, students learn
to transform ideas into new concepts and insights with a greater
appreciation for the natural world. Our presentation will show-
case the design, fabrication and installation of the large-scale
public art created in the Art/Science Fusion program. Nature’s
Gallery is a new work displayed in the US Botanic Garden in
Washington DC. “Tree of Life” is a 10’ high x 17’ wide ceramic
mosaic mural at the UC Davis Arboretum. In addition, there
will be images of painted murals and textiles.

Donna Billick offers 32 years creating large-scale public art

in America, and around the world. I believe that the issue of
collective meaning and purpose is essential and urgent, due to
environmental pressures. Our social choices and outcomes are
shaped by two systems, our nature or physical world and our
cultural heritage or artifacts. I believe a parallel vision for a fu-
ture that supports our mind, body and soul is created in fusion
concepts.

Julie Newdoll: Paintings based on microbiology

Emotions, states of being, and nature have been personified
throughout time by many cultures in the form of various gods,
goddesses and mythical characters. Julie Newdoll asks the
questions, “Just as Bacchus can represent wine and the state
of intoxication, Venus love, and Mars war, what would the
personality of a goddess for estrogen be like? What would be

her life story? Our imaginations seek to see things in nature in
order to make sense of them. We see constellations in the stars
and faces in the clouds.

What would we see in an electron microscope image if we
looked long enough?” Newdoll’s artwork has been featured
on over 20 scientific journal covers in the last few years, and
her paintings have been shown in both science and art venues
internationally. Newdoll earned a B.A. in microbiology from
the University of California at Santa Barbara, and an MLS. in
medical illustration from the University of California at San
Francisco. You can find her work on the web at http://www.
brushwithscience.com and the Brush with Science Gallery,

3515B Edison Way, Menlo Park, California (650) 440-0084.

Shoshanah Dubiner’s biological images

We will project 11 paintings by Shoshanah Dubiner of Ash-
land, Oregon, who has been fascinated by biological forms for
many decades. After a recent Cell Biology class at Southern
Oregon University, Shoshanah is turning her attention to the
structures of the living cell, especially the cell membrane. She
brings humans into all the landscapes, so viewers can imagine
themselves more fully in the world of nature. Thus in “Mem-
branes #1,” the cell at the top left is also the head of a woman;
the cell membrane becomes the skin that encloses her body; the
words issuing from her mouth take on a life of their own, as do
all the artifacts of human culture, including artists’ paintings.

YLEM JOURNAL: Vol. 27, No.6 3

ROBOT ART: A NEW KIND OF ART
Leonel Moura
http://www.leonelmoura.com

Mankind has been intrigued by the possibility of
building artificial creatures. For the ancient Greeks
this possibility was provided by techné, the procedure
that Aristotle conceived to create what nature finds
impossible to achieve. Hence, under this view, techné
sets itself up between nature and humanity as a cre-

ative mediation.

This was the path taken by Norbert Wiener as he
opened up the cybernetic perspective, viewed
as the unified study of organisms and machines
[1]. One line of development linked to this
approach gave rise to the familiar human-
oid robot, inspired by the von Neuman-
nian self-replicating automata and
based on the top-down attitude of
the earliest Artificial Intelligence [2].
A much more interesting trend, also
stemming from the seminal work of
Wiener but intended to “take the hu-
man factor out of the loop,” emerged in
the mid-1940’s with William Grey Wal-
ter, who proposed turtle-like robots that exhibit com-

Ant-like robot from the ArtSBot
project

plex social behavior. This was the starting point for a
new behavior-based robotics, abolishing the need for
cognition as mediation between perception and plans
for action.

This line of research was pursued in the 1980's by
Rodney Brooks [3], who began oe six legged
insect-like robots at MIT. This new
generation of robots was based on
Brooks’ “Subsumption Architecture,”
which describes the agent as com-
posed of functionality distinct control
levels under a layered approach. The
addition of new layers doesn’t imply
changes in the already existing layers.

bots is “situatedness,” which means that the robot’s
behavior refers directly to the parameters sensed in
the world, rather than using inner representations.
Linked to this concept is the “embodiment” feature,
which corresponds to the fact that each “robot is a
physical body and experiences the world directly
through the influence of the world in that body”.

The idea of collective robotics appeared in the 1990’s
from the convergence of the above described Brooks’
architecture with a variety of bio-inspired algorithms,
focused on new programming tools for solving dis-
tributed problems. These bio-inspired algorithms
stemmed from the work of Christopher Langton,
who launched a new avenue of research in Al
denoted Artificial Life that “allows us to
break our accidental limitations to car-
bon-based life to explore non-biological

forms of life” [4].

The well-known collective behavior of

ants, bees and other eusocial insects pro-
vided the paradigm for the swarm intel-
ligence approach of aLife. This bottom-up
course is based on the assumption that
systems composed of a group of simple
agents can give rise to complex behavior,
which depends only on the interaction between those
agents and the environment. Such an interaction may
occur when the environment itself is the communica-
tion medium and some form of decentralized self-or-
ganized pattern emerges without being planned by
any exterior agency.

Based on ants and other social insect’s
studies [5], I have tried to reproduce
artificially a similar emergent behavior
in a robot swarm. These insects com-
municate among themselves through
chemical messages, the pheromones,
with which they produce certain pat-

: ¥S ns as
The aforementioned control levels 4 swarm of ant-ltke robots at work

then act in the environment without

supervision by a centralized control or action plan-
ning centre. Also, no shared representation or any
low bandwidth communication system is needed.

The most important concept in Brooks’ reactive ro-

4 YLEM JOURNAL: Vol. 27, No. 6

terns of collective behavior, like fol-
low a trail, clean up, repair and build
nests, defense and attack or territory conquest. De-
spite pheromones not being the exclusive way of com-
munication among these insects — the touch of anten-
nas in ants or the dance in bees are equally important
— pheromonal language produces complex cognition

via bottom-up procedures. Pheromone expression is
dynamic, making use of increments and decrements,
positive and negative feedbacks. Messages are ampli-
fied when a pheromone is reinforced,

with intense shapes of color. In other words, initial
randomness generates “order.” The process is emer-
gent and based on the properties of stigmergy.

and lose “meaning” when a breeze dis-
perses it. It is also an indirect form of
communication, coined vtigmergy by
Grassé [6], from the Greek stigma/sign
and ergon/action. Between the indi-
vidual who places the message and the
one who is stimulated by it, there is no
proximity or direct relation.

Following these principles, I have re-
placed pheromone by color in my first

Machine creativity

The artistic product of these robots is
entirely original. In the same way that
somebody who writes a book cannot
be considered as a mere instrument
of his primary school teacher, robots
cannot be seen as simple instruments
of the artist that conceived and pro-
grammed them. There is an effective

incorporation of new and non prede-

ant-robots (2001). The marks left by ArtSBot (020404
one robot triggers a pictorial action in

other robots. Through this apparent random mecha-
nism abstract paintings are generated, which reveal
well-defined shapes and patterns. These robots cre-
ate abstract paintings that seem at first sight just ran-
dom doodles, but after some reflexive observation,
color clusters and patterns become patent. Through
the recognition of the color marks left by a robot, the
others react to it, reinforcing certain color spots. The
process is thus everything but arbitrary. As far as I
know, ArtSBot (Art Swarm Robots) [7] was the first
art project to use emergent organization for devel-
oping robot creativity. Every

termined information in the process.
And that cannot be called anything but
creativity. It is true that consciousness is lacking in
this creativity. But if we look at the history of modern
art, it is obvious that, for example, Surrealism tried to
produce art works exactly in these same terms. The
“pure psychic automatism,” the quintessential defini-
tion of the movement itself, appeared as a technique
that was spontaneous, non-conscious and without any
aesthetic or moral intention. In the first Surrealist Man-
ifesto, André Breton (1924) defined the concept in this
way: “Pure psychic automatism by which it is intend-
ed to express, either verbally or in writing, the true

function of thought. Thought

previous experiment focused
exclusively on randomness or
sometimes on target strategies
leading the machines to fulfill a
pre-determined program creat-
ed by the human artist. On the

contrary, ArtSBot was meant

dictated in the absence of all
control exerted by reason, and
outside all aesthetic or moral
preoccupations.” [8]. In the
field of the visual arts, Pollock
better fulfills this intention by
splashing paint onto the can-

to put into practice the utmost

ArtSBot 280404

possible machine autonomy,

aimed at producing original

paintings. In operational terms, ArtSBot consists of a
series of small “turtle” type robots, equipped with two
felt pens and a pair of RGB sensors pointing to the
painting plan. With these “eyes” the robots seek color
(chromotaxis), determine if it is hot or cold, choose
the corresponding pen and strengthen it by a constant
or variable trace. To begin the process, when the can-
vas is still blank, the robots leave here and there a
small spot of color randomly. Based on these simple
rules, unique paintings are produced: from a random
background stands out a well defined composition

vas with the purpose of repre-
senting nothing but the action
itself. This was coined Action
Painting. Perhaps, because of that, the first paintings
from my robots are, aesthetically, similar to those of
Pollock or André Masson, another important automa-
tism-based painter. In his surrealist period, Masson
tried frequently to prompt a low conscious state by
going hungry, not sleeping, or taking drugs, so that
he could release himself from any rational control and
therefore let emerge what at the time, in the path of
Freud, was called the subconscious. The absence of
conscious, external control or pre-determination al-
low these painting robots to engender creativity in its

YLEM JOURNAL: Vol. 27, No.6 5

pure state, without any representational, aesthetic or

moral intention.

RAP (Robotic Action Painter), created in 2006 for
the Museum of Natural History in New York, is an
individualist artist and not a swarm, but makes use
of the same composition methods based on stigmer-
gy and emergence. This robot is additionally able to
determine, by its own means, the moment in which

onboard chip, to which the program that contains the
basic rules is uploaded through a PC serial interface.

The algorithm that underlies the program uploaded
into RAP’s microcontroller induces basically two
kinds of behavior: the random behavior that initial-
izes the process by activating a pen, based on a small
probability, whenever the color sensors read white;
and the positive feedback behavior that reinforces

the painting is finished. Previous versions
didn’t have this capacity, being conditioned
by battery discharge or my will to stop the
process. RAP’s decision is taken based on
the information that it gathers directly from
the painting, which produces a consider-
able variation of time and form, since RAP
can decide that the work is complete after a
relatively short while (entailing accordingly

a low pictorial expression) or can extend es

the color detected by the sensors, activat-
ing the matching color pen. These two dis-
tinct behaviors are described as modes: the
Random Mode and the Color Mode. In
the random mode RAP searches for color
(chromotaxis). If a sufficient amount is not
found (threshold) RAP activates here and
there, randomly, a pen stroke choosing also
randomly the color and the line configura-

tion. The shape, orientation and extent of

(wos
the picture construction for a quite long pe- 4”SBot 010504

riod, making it much more dense and com-

plex. The “secret” of this behavior is in the significant
change of the sensors, which passed from two to nine
“eyes,” allowing now the reading of local patterns, in
addition to color spots. RAP is also my first robot to
sign its works.

ISU, the poet robot also created in 2006, has the abil-

ity to write letters and words producing poems and

these initial lines are determined by the ro-
bot based on a random seed acquired from
its relative position in the space. This is done with the
data retrieved by the onboard compass. In this way
RAP’s random generator can be described as real ran-
dom and not pseudorandom.

When a certain amount of color is detected the robot
stops the random behavior and changes to color mode.
In this phase RAP only reacts to the spots where a
certain amount of color is found, reinforcing it with

emergent compositions based on the letter, quite simi-

rt

larly to the Lettrism style, an artistic
movement that followed Surrealism.

These references to 20th century
art movements do not seek any kind
of historical legitimacy, but are in-
tended simply to show how certain
morphogenesis processes produce Lf res

i og . .
similar results in human as well as t

the same tone.

After a while a discrete pattern
emerges, where from a general ran-
dom background a_ well-defined

composition can be recognized.

In order to determine when the

non-human artists. Demonstrating, 4? 250807

in the path of Rodney Brooks, how

human nature can be seen to possess the essential
characteristics of a machine.

RAP’s behavior

RAP is equipped with a grid of 3x3 color detection
sensors, eight obstacle avoidance sensors, a compass,
a microcontroller and a set of actuators for locomo-
tion and pen manipulation. The microcontroller is an

6 YLEM JOURNAL: Vol. 27, No. 6

painting is finished, RAP makes
use of a grid of 3x3 RGB sensors.
If a certain pattern is found, the robot “considers” the
work to be done, moves to the down right corner and
signs.

RAP creates artworks based on its own assessment of
the world. At any given moment the robot “knows”
its situation and acts accordingly. It scans constantly
the canvas for data retrieving. It uses its relative posi-
tion in the space asa real random generator. It builds
gradually a composition based on emergent proper-

ties. It decides what to do and when to do it. It finishes
the process using its particular sense of rightness.

Although the human contribution in building the
machine and feeding it with some basic rules is still

we humans are for the time being the only pensive ob-
servers, the relation between machine art and human
aesthetic principles is here the central issue. Many
people like the robot paintings, probably because we
seem to gladly embrace fractal and chaotic structures.

significant, the essential aspects
of RAP’s creativity stem from the
information that the robot gathers
by its own means from the environ-
ment. In this sense RAP’s art must
be seen as an original creation in-
dependent of the human artist that
was at the origin of the process.

A new kind of art

My painting robots were created to

paint. Not my paintings but their

But, more than shapes and colors,
what some of us really appreci-
ate in this idea and its associated
process is the fact that it questions
some of our strongest cultural con-
victions. Art was supposed to be
an exclusive matter of mankind. In
this sense, the robot paintings are
a provocative conceptual art that
problematizes the boundaries of
art as we know it.

References

own paintings. The essence of their 4? 180906
creations stem from the machines’

own interpretation of the world and not from its hu-
man description. No previous plan, fitness, aestheti-
cal taste or artistic model is induced. These robots are
machines dedicated to their art.

Such an endeavor addresses some of the most critical
ideas on art, robotics and artificial intelligence. Today
we understand intelligence as a basic feedback mech-
anism. If a system, any system, is able to respond to
a certain stimulus in a way that it changes itself or its
environment, we can say that some sort of intelligence
is present. ‘Sheer’ intelligence is therefore something
that doesn’t need to refer to any kind of purpose, tar-
get or quantification. It may plainly be an interactive
mechanism of any kind, with no other objective than
to process information and to react in accordance to
available output capabilities.

Hence and although my starting point was bioinspira-
tion, in particular modeling social insects’ emergent
behavior, the idea was to construct machines able to
generate a new kind of art with a minimum of fitness
constraints, optimization parameters or real life sim-
ulation. It is the simple mechanism of feedback and
stigmergy that is at work here.

These artistic robots are singular beings, with a par-
ticular form of intelligence and a kind of creativity of
their own. They do art as other species build nests,
change habitats or create social affiliations. But since

[1] Wiener, N. (1948) Cybernetics; or the Control and
Communication tn the Animal and the Machine, MYT
Press.

[2] von Neumann (1966) Theory of velf-reproducing au-
tomata, ed. By A.W. Burks, University of Illinois.

[3] Brooks, R., (1991) Zntelligence without Reason, Proc.
12th ISCAI, Ed. Morgan Kauffmann, San Mateo and
Brooks, R., (2002) Flesh and Machines: How Robots Will
Change Us, Pantheon Books.

[4] Langton, C. (1987) Proceedings of Artificial Life, Ad-
ison- Wesley.

[5] Wilson, Edward O. (2006) Nature Revealed, Selected
Writings 1949-2006, The Johns Hopkins University
Press, Baltimore.

[6] Grassé, P. P. (1959) La réconstruction du nid et les
coordinations tnter-tndividuelles chez bellicositermes nata-
lienses et cubitermes sp. La théorie de la stigmergie: Essat
dinterpretation des termites constructeurs, Insectes So-
ciaux, 6, pp. 41-48.

[7] Moura, L. and Pereira, H.G. (2004) Man and ro-
bots: Symbiotic Art, Institut d’Art Contemporain, Vil-
leurbanne.

[8] Breton, André (1969) Manifestoes of Surrealism,
University of Michigan Press.

YLEM JOURNAL: Vol. 27, No. 6 7

CHANCE IN ROBOTIC PAINTING
Max Chandler
http://www.maxchandler.com

“The original movement, the agent, is a point that sets
itself in motion (genesis of form). A line comes into
being. It goes for a walk.”

—Paul Klee

Paul Klee wrote a short text he titled “Taking a Line

I make autonomous mobile robots that are small
enough to walk around the canvas using paint brush-
es to make marks. The robots have a small computer
on board and sensors that can see the surface of the
canvas and the marks it has already made. I use these
robots a as a tool for painting — as a super brush that
can make marks that humans cannot make alone. For
instance, the robots can stay much closer to the ac-
tual lines of living growing things than we can with
hand eye coordination. They are also capable of truly
random behavior that brings them closer to natural

I wish to make art that reflects our common lives. Two Ken Goldberg, a prominent artist in the Bay Area, of-

aspects of 21st century life are inescapable. First isthe ten uses robots in collaborative social environments

continuing discoveries and refinement of knowledge where people all over the globe can direct these robots

through science. I think the contempo-
rary disrespect and distrust of science
may be temporarily fashionable, but is
certainly eternally foolish. Second, most
of us have become personally engaged
with technology. Technology is no lon-
ger limited to impacting our work lives,

smart devices have a role in our personal

in various tasks. One of his best known
works was a garden tending by a robot
that was controlled by users through
the Internet.

Artists like these are using robots as part
of a larger vision. The robot is a tool or
a component of the work rather than a

for a Walk.” To give this idea a 21st century twist, variation.

—_—

Fragments of a logarithmic spiral

8 YLEM JOURNAL: Vol. 27, No. 6

lives as well. Who would claim their daily
lives are not changed by one or more of

the following devices: cell phone, TIVO,

part of their make up. These devices in-
volve a combination of mechanics, elec-
tronics, controllers, and programming.
Using a similar tool to make art reflects who
we are and our lives today. I use simple, very
focused, small robots as a tool to integrate both
aspects into an art that is science informed and
engaged with technology in obvious and not
so obvious ways. I have seen many art projects
that use similar devices.

ELF is an art team from Germany that makes

small insect-like robots that they display in
jars. The robots chirp, kick against the jars and

a’

Blackberry, Notebook Computer, In-
tenet Search Engine, eMail Servier,...? Great advances have been made in re-
Cell phones are a constant companion of cent years in thinking about small ro-
many people today. bots. Through the work of Rodney

Brooks, Mark Tilden, and many others,
These are all smart devices that depend we now realize that simple robots, man-
upon small to large computers that are aging simple behaviors, are often much

struggle to climb out. It is an interest-
ing display that takes on a special slant
when you see their film. The film shows
these robots “living” in natural settings
— trees, grass, beaches, etc. — then peo-
ple come along, collect them and place
them into the jars. Because the jars are
European, American viewers may not
get it right away. If they were in the

substitute for the artist. This is much

closer to the actual use and capabilities
of robots than earlier approaches.

more successful than robots that try to
be substitute humans or pursue human-
like solutions.

Most people realize that painting with robots
involves calculations — many calculations.
To just move around an autonomous mobile
robot uses calculations for motor control, po-
sition deduction and so on. Also, mathematics
provides a rich palette of shape description
functions. I choose from algorithms that the
shapes, lines and patterns in growth of living
organisms. There are many texts that explain
the mathematics that explain natural shapes
qi and growth patterns. Here area few:

“The Self Made Tapestry” and “Criti-
cal Mass” by Philip Ball

“The Algorithmic Beauty of Sea Shells”
by Meinhardt, et al

“The Algorithmic Beauty of Plants” by

Prusinkiewicz and Lindenmayer

“On Growth and Form” by D’Arcy

same mason jars they we used to capture Wark yariation due to COGS Thompson

fireflies or other insects as kids then our

experience would be like the European viewer. Many
of us have treated living creatures the way these ro-
bots have been treated.

“A New Kind of Science” by Stephen
Wolfram

Article continued on the next page

YLEM JOURNAL: Vol. 27, No.6 9

My cacti series of paintings use fragments of logarith-
mic spirals for edges and lines and cellular automata
rules for shape selection and placement.

The prickly pear cactus family (Opuntia) is a group
of plants whose growth is amazingly like cellular au-
tomata. Its pads are like cells in that they are mostly
alike and their number, position and type depend
upon the number, position and type of their neigh-
bors. Each pad uniquely defines the cactus. You can
propagate the plant by cutting off a pad and placing
partly in the ground. One method the plants use for
propagation is to drop pads onto the ground when
they become crowded or water becomes scarce. The
pads get moved by animals and take root in a new lo-
cation. There are three basic types of pads. Base pads
connect to the root systems and later (20 to 70 years
later) turn into woody trunks and branches. End pads
flower and produce fruit for one or more years and
then produce a number of new end pads. The bulk
of the pads are links between base and end pads. The
number and branching of links varies by species. Al-
though as many as ten new end pads can be gener-
ated, all but one or two (in some species, three) of the

pads will drop off in the next few years. Which pads

remain to become the structure of the plant have a cel-

lular automata like dependency upon its neighbors.

To me, a great danger of art with robots is that it can
become predictable, routine, even rubber stamp-like.

ibe you look at a group of blossoms on a plant you can
see two characteristics. First, each flower is logically
composed the same way, with the same center and
pattern of petals. Second, no two of the actual flowers
are physically alike. The orientation of the bloom to

10 YLEM JOURNAL: Vol. 27, No. 6

the sun and the plant varies. Some petals are slightly
shorter, some twist, some turn down, and on and on.

Robotic devices can use several tactics to obtain this
natural variation.

Most of my robots are walking robots, which have
center of gravity shifting (COGS) as they walk. Of
course, anything that walks has COGS, humans in-
cluded. Design of walking robots often concentrates
on limiting COGS effects by shifting weights, twisting
ankles, etc. My robots take the opposite direction to
capitalize on COGS effects and the resulting impact
on brush dynamics. GIMPY1, for instance, is unusu-
ally wide for an autonomous mobile robot, as a way to

emphasize COGS effects.

Randomization has been used in art in the past by Du-
champ, Cage, Johns, and others. These artists have
mostly used dice as a source of random numbers for
selection or placing content in their images. Dice are
a very weak source of random numbers compared to
the capabilities of even simple microcontrollers. Even
8-bit microcontrollers that support Java have 32-bit
random number generation, which is like rolling mil-
lions of dice. We use this capability to control the

——S : =

range, precision, and randomness of the numbers far,

far beyond the reach of dice. Early randomization in
art was just moving erratically through a small (often
very small) pattern. Today, we can actually get much
closer to natural variation.

My robots are almost all programmed in Java, so a lot
of the code is reused between them. To do this I have
a profile for each robot including forward speed, turn-
ing speed, balancing factors, sensors thresholds, hys-

teresis, etc. I can add or subtract a random amount to
these profiles to produce smoothly varying behaviors
for the robot during the course of making an image.

Most robotic mark makers are plotter-like, so I choose
ballpoint pens or markers that produce the same mark
regardless of the speed or direction of the robot. Be

Because nearly all of my robots depend upon two
motors for forward motion there is a problem getting
straight line motion since individual motors vary in
their performance. Initially, I set up test devices so
I could measure each of my motors and then select
well matched pairs. This turns out to be expensive.
Sometimes I had to buy 5 motors to get a good pair.
More important; my robots operate for hundreds and
hundreds of hours while stopping and starting on
sub-second intervals. This causes the motors to wear

over time and they don’t wear evenly, so motor pairs
that started with performance curves no longer match
in a few months. To overcome this I use software to
balance the motors by commanding the slow one to go
a little faster. Now, minor tuneups by measuring and
revising the profile keep my robots working well for
years. For more sophisticated motor circuits there are
better solutions, of course.

cause I use many marking devices — paint brushes,
rollers, sponges, sticks, palette knives, rags and more
— I need a brush control that allows all of the robot's
dynamics to transfer to the marking device. Through
many trials and many, many errors | have learned that
loose couplings work much better than rigid ones.

A filmmaker who was filming me painting asked, “If
it’s art by robots, why are you so busy?” First, it’s
art with robots. The robot does not make it easier to

paint, but does make the painting special. The speed
of the robot is set to make good brushwork, but it
runs continuously. When I paint by hand I can pause
between each brush stroke so there really isn’t much
of a speed requirement. Not so when working with
a robot. The robot keeps walking and responding to
what it sees while I load brushes with paint and place
them in the robot. I usually work with the robot in a
number of sessions each about 20-30 minutes. Then I

YLEM JOURNAL: Vol. 27, No.6 11

os

have to wait. It is usually not good to have the robot
walk through wet paint. Sometimes it looks OK for
the robot to walk in wet paint, but the paint can “kick
up” from the feet and into the gears and motors which
leads to earlier death of these parts. So I work in a ses-
sion that is a layer or a section of the total image and
then study the results and plan the next session while
the paint dries. With acrylics in Arizona this is about
an hour, but sometimes more for thicker paint. Before
I begin a painting I mix more than enough paint col-
ors to last for the total picture. I havea large holder of
more than 100 brushes (many are alike). I drop used
brushes into water during sessions and clean up all
brushes between sessions.

I also use a lot of clamps of various sizes for control-
ling brush depth and orientation. Early sessions may
also use paper cutouts to define initial shapes.

Sometimes I use multiple brushes. This lets colors
blend on the canvas and some parallel lines as well
One small brush with intense color and a large flat
brush with lighter color can produce a blended edge.

12 YLEM JOURNAL: Vol. 27, No. 6

The sessions can be very hectic. If I am not ready
when a new brush is needed, I might miss a curve
or starting point that I felt was important. I prepare
borders on the table around the canvas so that the
robot will walk back onto the canvas if it walks off.
Some sessions go well, almost like a long, long dance.
Sometimes the sessions are so frantic, I feel like a mad
scientist. What counts in the end, though, is not how
the session felt, but what image was made. When I
first began, I destroyed or painted out more than 80%
of the paintings I made. Now I am better, so I only
paint out about 45%.

In his book Jazz, Matisse said, “In art, truth and re-
ality begin when you no longer understand anything
you do or know.” In my work, I reach this state of
mind in the rhythm and speed of the sessions. There is
always in my work a strong conflict between plan and
actual and I think much of emotional appeal comes
from that conflict.

Recently, I painted a very large guitar as part of Gui-
tarmania, a public art project to benefit Big Broth-
ers Big Sisters. The guitar was an exact replica of a
Fender Stratocaster and was ten feet tall. Because
none of the surfaces were actually flat, it turned out
to be much more difficult than I expected. The robots
would fall over or even fall off the guitar completely.
I had to work in very short brushstrokes to overcome
these problems.

To complete this guitar took more than 230 hours and
used up over 200 AA batteries. The guitar was dis-
played on Mill St in Tempe, AZ very near the ASU
campus for about four months and then was auctioned
for charity and is now in the lobby of a company in
Phoenix.

YLEM JOURNAL: Vol. 27, No. 6

Here are some examples of my work:

14 YLEM JOURNAL: Vol. 27, No. 6

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YLEM

BOARD OF DIRECTORS
Torrey Nommesen: President
Julie Newdoll: Vice President

Loren Means: Treasurer
Kristine Brown: Secretary
Stephen Wilson

ADVISORY BOARD

Ruth Eckland

Independent Artist

Theodosia Ferguson

Intl Society for Arts, Sciences, Technology
Nathan Friedman

Mathematics Dept., SUNY Albany
Robert Gelman

Multimedia Artist, producer

Lucia Grossberg-Morales
Independent Artist

Molly Hankwitz

Independent Arist

Eleanor Kent

Artist/Curator

Barbara Lee

Independent Artist

Roger Malina

Center for Extreme Ultraviolet Physics
Mike Mosher

Saginaw Valley State University

Dr. Clifford A. Pickover

IBM Thomas J. Watson Research Library
Trudy Myrrh Reagan

YLEM founder

Mary Stieglitz

Art and Destgn Dept., Towa State University
Larry Shaw

Curvatial Photography

Fred Stitt

San Francisco Institute of Architecture
Patricia Tavenner

UC Berkeley Extension

Joan Truckenbrod

School of the Art Institute of Chicago

JOURNAL
Loren Means: Executive Editor
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Trudy Myrrh Reagan: YLEM founder

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Torrey Nommesen

YLEM JOURNAL: Vol. 27, No.6 15

YLEM

JOURNAL

artists using science and technology

ylem [pronounced eye-lem]
-noun

1. Greek: for the exploding mass from which the
universe emerged; the material of the universe
prior to creation.

YLEM is an international organization of artists, scientists, authors, curators,
educators and art enthusiasts who explore the Intersection of Arts and Sciences.
Science and Technology are driving forces in contemporary culture, and YLEM
members strive to bring the humanizing and unifying forces of art to this arena.
YLEM members work in contemporary media such as Computer-Based Art, Kinetic
Sculpture, Interactive Multimedia, Robotics, 3D Media, Film and Video.

CONTACT INFORMATION

MEMBERSHIP
members@ylem.org

JOURNAL

Loren Means

149 Evelyn Way

San Francisco, CA 94127
USA

lorenmea@pacbell.net

www.ylem.org

16 YLEM JOURNAL: Vol. 27, No. 6